INI-CET 2026 - Physiology Practice Questions

Q: If a patient is on testosterone therapy, what changes can one see in LH and FSH levels?

Decreased LH, decreased FSH. ***Decreased LH, decreased FSH*** - Exogenous **testosterone** exerts strong **negative feedback** on the **hypothalamic-pituitary-gonadal (HPG) axis**. - This suppression leads to reduced secretion of **Gonadotropin-Releasing Hormone (GnRH)**, which subsequently lowers the release of both **Luteinizing Hormone (LH)** and **Follicle-Stimulating Hormone (FSH)** from the anterior pituitary. *Increased LH, decreased FSH* - **LH** levels would not increase because **testosterone** suppresses the pituitary's output of gonadotropins rather than stimulating it. - This pattern does not correspond to the physiological effect of testosterone administration on the feedback loop. *Decreased LH, increased FSH* - While **LH** would indeed decrease due to negative feedback, **FSH** would also be concurrently suppressed, not increased. - There is no mechanism in this context for isolated **FSH** increase while receiving androgen therapy. *Increased LH, increased FSH* - This pattern is characteristic of **primary hypogonadism**, where the testes fail to produce testosterone, thus removing the negative feedback on the pituitary. - With exogenous **testosterone** administration, the opposite effect occurs (suppression rather than elevation).

Q: During oral rehydration therapy in diarrhoea, which transporter is most active in promoting fluid absorption?

SGLT1. ***SGLT1*** - SGLT1 (Sodium-Glucose Linked Transporter 1) is a symporter that transports **glucose and sodium** across the apical membrane of the enterocyte, which creates an **osmotic gradient** driving massive water absorption. - This mechanism remains intact even during secretory diarrheas, forming the physiological basis for **Oral Rehydration Therapy (ORT)** effectiveness. *CFTR* - The CFTR (Cystic Fibrosis Transmembrane Conductance Regulator) is a chloride channel responsible for **secreting chloride** ions into the intestinal lumen, which drives fluid secretion. - Its activity is often pathologically upregulated in diarrheal diseases like **cholera**, contributing to the loss of fluids and electrolytes rather than absorption. *NHE* - The NHE (Sodium-Hydrogen Exchanger) is a sodium transporter involved in neutral sodium absorption primarily in the **jejunum and ileum**. - While it contributes to normal sodium uptake, it is not the target mechanism exploited by ORT solutions containing glucose to maximally stimulate fluid uptake. *Na+-K+ ATPase* - Located on the **basolateral membrane**, this pump maintains the electrochemical gradient by pumping sodium out of the cell and potassium into it. - While essential for secondary active transport, it provides the low intracellular sodium concentration necessary for transporters to function but is not the apical gateway utilized for **glucose-coupled uptake**.

Q: Identify the skin receptor shown in the image:

Pacinian corpuscle. ***Pacinian corpuscle*** - These are **large, encapsulated mechanoreceptors** characterized by a distinctive 'onion-like' appearance due to multiple concentric lamellae of connective tissue. - Located deep in the dermis and subcutaneous tissue, they are specifically adapted to detect **high-frequency vibration** and deep pressure. *Merkel disc* - These are non-encapsulated receptors located in the **stratum basale** of the epidermis. - They function primarily as **slowly adapting** receptors responsible for sensing **fine touch** and texture. *Ruffini ending* - These appear as spindle-shaped receptors located deep within the dermis and joint capsules. - They are **slowly adapting** mechanoreceptors that detect **skin stretch** and sustained pressure. *Meissner corpuscle* - These are encapsulated receptors located in the **dermal papillae** of glabrous (hairless) skin. - They are **rapidly adapting** receptors that specialize in detecting **low-frequency vibration** and light touch.

Q: Intercalated disc is composed of: 1. Cadherins 2. Desmosomes 3. Gap junctions 4. Tight junctions

1, 2 and 3. ***1, 2 and 3*** - Intercalated discs contain **fascia adherens** (containing **cadherins**) and **desmosomes** which provide strong mechanical adhesion, preventing cells from separating during contraction. - **Gap junctions** are essential components of the intercalated disc, allowing for the rapid passage of ions and electrical impulses, which facilitates **functional syncytium** behavior of cardiac muscle. *2, 3 and 4* - While desmosomes and gap junctions are correct, **tight junctions** are not typically components of the intercalated disc. - Tight junctions function primarily to create permeability barriers in epithelial and endothelial tissues, not in contractile cardiac muscle. *1, 3 and 4* - While cadherins and gap junctions are correct, **tight junctions** are not present in cardiac intercalated discs. - Tight junctions are characteristic of the **blood-brain barrier** or intestinal lining, meant for regulating paracellular transport. *1, 2, 3 and 4* - Including **tight junctions** makes this option incorrect, as they are not structural components of the cardiac intercalated disc. - The intercalated disc is specialized for mechanical cohesion and electrical coupling, not for maintaining epithelial-like tight barrier functions.

Q: Which of the following statements regarding hormones and their metabolic actions are correct? A. Insulin increases protein synthesis B. Thyroxine decreases basal metabolic rate C. Insulin decreases blood glucose levels D. Epinephrine increases glycogenolysis E. Glucagon increases gluconeogenesis

A, C, D and E only. ### ***A, C, D and E only*** - **Insulin** acts as a potent anabolic hormone, stimulating amino acid uptake and intracellular **protein synthesis**, while simultaneously lowering **blood glucose levels** by facilitating glucose uptake into tissues like skeletal muscle and adipose tissue. - **Epinephrine** stimulates glycogen breakdown (**glycogenolysis**) in the liver and muscle for rapid energy, while **Glucagon** elevates blood glucose by promoting **gluconeogenesis** and glycogenolysis, primarily in the liver. *A, B and C only* - This option includes **Thyroxine**, which is incorrect because thyroid hormones are key regulators that **increase the basal metabolic rate (BMR)**, not decrease it. - Therefore, any set containing statement B is fundamentally incorrect. *A, C and D only* - While A, C, and D are correct, this combination is incomplete because statement **E (Glucagon increases gluconeogenesis)** is medically accurate. - Omitting statement E makes this option inferior to the fully comprehensive answer. *All of the above* - This option is incorrect because it includes statement B, which contradicts the established physiological role of **Thyroxine**. - Thyroxine is calorigenic and consistently acts to raise the body's **metabolic rate**.

Question 1

If a patient is on testosterone therapy, what changes can one see in LH and FSH levels?

Accepted Answer

Decreased LH, decreased FSH

Answer

Increased LH, decreased FSH

Answer

Decreased LH, increased FSH

Answer

Increased LH, increased FSH

Question 2

During oral rehydration therapy in diarrhoea, which transporter is most active in promoting fluid
absorption?

Accepted Answer

SGLT1

Answer

CFTR

Answer

NHE

Answer

Na+-K+ ATPase

Question 3

Identify the skin receptor shown in the
image:

Accepted Answer

Pacinian corpuscle

Answer

Merkel disc

Answer

Ruffini ending

Answer

Meissner corpuscle

Question 4

Intercalated disc is composed of:

1. Cadherins
2. Desmosomes
3. Gap junctions
4. Tight junctions

Accepted Answer

1, 2 and 3

Answer

2, 3 and 4

Answer

1, 3 and 4

Answer

1,2, 3 and 4

Question 5

Which of the following statements regarding hormones and their metabolic actions are correct?

A. Insulin increases protein synthesis
B. Thyroxine decreases basal metabolic rate
C. Insulin decreases blood glucose levels
D. Epinephrine increases glycogenolysis
E. Glucagon increases gluconeogenesis

Accepted Answer

A, C, D and E only

Answer

A, B and C only

Answer

A, C and D only

Answer

All of the above

INI-CET 2026 — Physiology